I just completed servicing the Leslie motors in our Leslie 122 at the church so I thought I'd post some tips for those who may want to do the same with their Leslie or their church's Leslie. First and foremost, go to
http://www.bentonelectronics.com/lesliemotor.html and print this out. This website is an excellent resource that will help you understand how to disassemble and reassemble a Leslie motor.
Most single speed Leslie speakers have oil tubes in the back of the cabinet that allow you to oil the motors without having to take anything apart. These tubes run down into a pan on the motor covered by a felt pad. The oil on the felt pad will keep the top and bottom bearings lubricated. There is a slot on the panel that goes into the upper bearing, and a tube that runs down to the lower bearing. Personally, I feel this method is not sufficient. I am a firm believer in removing the back panels and completely taking the motors out for disassembly. This way, you can kill 2 birds with one stone by cleaning and oiling both motors. If the motors haven't been serviced in years, there's a good chance the motor has gummed up oil and oil-saturated dust. Inside the motors are another set of felt pads around each bearing. After you have cleaned all the parts (You can use something like WD-40) oil the internal felt pads. I recommend using Leslie or Hammond oil, but if you have something like sewing machine oil, that will do. I have used both standard Leslie/Hammond oil and a 3 in 1 oil. Oil the internal felt pads until they are shiny and make sure they stay that way. Sometimes it takes a minute for the oil to completely soak in, so don't assume it's been sufficiently oiled until the felt pad looks like it's completely full. Despite what the manual says about over-oiling, I believe a little over-oiling is okay and even necessary. These motors are built like tanks and can endure just about anything. Be sure to spread some oil on the shaft and armature before reassembly. Once everything is back together, oil the felt pad in the oil pan. You probably don't need to put as much oil in there since you've oiled the internal pads. However, it's up to you.
Now for dual motor stacks, you'll have no choice but to remove the motors from the cabinet. There are no oiling tubes or oiling pans. First separate the slow motor from the fast motor. Next disassemble the fast motor so you can clean it and oil each felt pad. Basically it's the same process as with the single speed motors. The only extra thing you'll want to do is check the condition of the O-ring on the large pulley. If it looks worn, I would think about replacing it soon. Go ahead and reassemble the fast motor before you get started on the slow motor, that way you don't get any parts mixed up.
The slow motor is more delicate than the fast motor and usually will be the first go bite the dust after years of use. Fortunately they still make these brand new. They can be purchased for around $75 at
http://www.bborgan.com. In most cases, you probably won't have to completely disassemble this motor since everything is out in the open. However if you see that the armature bottoms out, I recommend taking out the spring on that shaft and stretching it some. Don't stretch it too far or there will be too much tension and may not allow the shaft to disengage from the fast motor. Basically you want to tension it enough to where it doesn't bottom out. The armature takes a few seconds to completely stop spinning after it's been disengaged. So if it bottoms out while spinning, it can damage the armature and bearing. Make sure there is no oil on the shaft or on the fast motor O-ring. This will cause problems and may keep the rotors from spinning at chorale speed. If the slow motor looks relatively clean, you'll need to oil both bearings on the motor. There are small holes on each end bell. Remove the slow motor mounting plate so you'll have access to the oiling hole. This is a rather time consuming process. I recommend anywhere from 30 to 40 drops, YMMV. Wait until the oil drains into the felt pad inside before sticking another drop in there. Have a paper towel handy or something to wipe the excess oil off. You don't want it running off into the shaft.
Finally after both motors have been cleaned and reassembled, you'll need to adjust the slow motor. A tight adjustment will keep the shaft from disengaging from the large pulley. A loose adjustment will not allow the shaft to make contact with the pulley thus, no slow speed. You'll have to periodically readjust the slow motor depending on how often it's being used.
Sometimes after reassembling the fast motor, when you first turn it on, it will lock up. This is applicable to both single speed motors and dual motor stacks and is very common. Just take a mallet and give it a good wack. Sometimes you have to do it more than once before the armature realigns itself. On the dual motor stack, check to make sure the slow motor shaft is making good contact and that it properly disengages from the pulley. Before sticking the motors back in the cabinet, I recommend wiping any excess dust out of the cabinet. And while your at it, stick some oil in the horn. That should do it and I'm sure your Leslie will operate much better.
One last thing, when taking these motors apart, don't be surprised if the washers on the shaft don't match what the diagram says. I've taken several of these motors apart and they don't always match. That's okay as long as it doesn't inhibit proper motor operation. The washers on the motors from the church Leslie were not even close to what the diagram says. In fact, a set of washers was on the outside of the motor and a lock ring to keep them in place. On the inside of the motor, only one side of the armature/shaft had a set of washers and another lock ring. This is okay though because the point of the washers is to minimize the amount of free play that the shaft has. There is also a "C" clamp around the belt pulley side of the shaft (it can be seen when you take the pulley off). There really no easy way that I've found to remove this. You may be able to maneuver it out of it's groove using a pocket knife. Obviously you'll want to be very careful doing that as the knife can sometimes slip. I used a screw driver with a small straight tip.
If you're really good, it should take no more than an hour per motor. I did a very thorough cleaning and oiling so it took me a little longer. Just take your time and try to learn something. For full details on how to service the motors I once again strongly urge you to check out that website. That will tell you everything you need to know. Well I realize this is a long post, but I hope it will help someone on this group.
Good luck and happy playing!
Ryan
